"What do you dislike about React Native?" June 2019 Edition

[cpojer]

The React Native team at Facebook would like to collect a list of problems that people are experiencing on the latest versions of React Native (0.59 or 0.60). This was done six months ago in "What do you dislike about React Native?" and now it is time to get another pulse to understand what's causing problems for people. Today, we posted an update about React Native on our blog which tracks the progress we have made towards the top concerns from last time.

Please reply with all the issues that you are having with current versions of React Native, one comment at a time. Keep your descriptions short and ideally link to other places with more context. Feel free to mention not just technical things but rather any issue related to the React Native project. Add hashtags for easier categorization.

If something has been mentioned already, please use the upvote/emoji buttons instead of repeating the same thing so that it's easier to see how many people care about each issue. Please make one comment per topic so that people can upvote just one thing at a time.

Hypothetical Example:

Documentation needs more pictures of cats and dogs

When reading the React Native documentation I tend to get frustrated. Have you considered adding pictures of cute dogs and cats to make them more relaxing to look at? #documentation

• Example of a comforting picture

Simple template with header (feel free to copy and paste)

### 

[RWOverdijk]

Live reload often causes issues

When using Typescript I have to reload my app often when using live reload. It does reload, but it shows the red screen with "Unable to find module for EventDispatcher". It has done this for a while. This combined with hot module reloading not working very stable causes some frustrations in dev. xcode also logs a lot of noise. There are plenty of issues about these things, too.

TL;DR; I guess for me it's #devExperience?

[jono-allen]

No documentation for adding build flavours for both platforms

Currently react-native only ships with debug and production builds. Quite often in a development stage, the use of multiple builds (Staging, QA, Sandbox) is beneficial. Would be an opportunity to better describe and add tools (maybe for the cli).

[jono-allen]

When adding native code warnings aren't clear that a new build is needed.

When adding a module. Often reloading the bundle the warnings can be confusing. I think like with react-native, a warning saying native modules are out of sync with a bundle or need a rebuild would be a good developer experience.

[jono-allen]

Imports are not from root.

When setting up a react-native project all imports are relative. It's very common that a developer will add babel-plugin-module-resolver. I would like to see this done in a way by default.

[jono-allen]

Cold start warnings.

React native doesn't have a friendly way to track down which modules are causing long startup times. I often struggle to track down these issues.

[AndreiCalazans]

Extend react-native cli to accept terminal commands

After starting the packager, I would like to be able to send commands to the running apps through the command line. It would be nice to accept commands for live reload, hot reloading, toggle debugger, and et cetera.

Doing so would improve developer experience, currently shaking the phone or using shortcuts to toggle the Dev Menu is a bigger hassle.

The available commands should be ideally displayed after you run react-native start

After dependencies are loaded:

Metro Bundler ready.

Loading dependency graph, done.

To hot reload press "r"
To restart the app press "R"
To toggle debugging mode press "d"

More commands could be included...

[ChuksFestus]

Expo!!!

Seriously the fact that you have to use expo to get this up and running is not cool. Don't get me wrong I like expo but it is usually very heavy so no matter how simple your app is, it will always be 20mb or more

[yinhangfeng]

Android JSC Crash

facebook/react-native#24261

[xzilja]

Assets for all resolutions are bundled with the app

Right now we can specify images for various screen resolutions by appending suffixes like @2x and @3x to their filenames. This gives benefit of performance on lower end / low res devices, but at the same time increases app size since all of these assets are included.

iOS solves this through combination of asset catalogs and bytecode enabled builds, where app store serves versions with correct image resolutions based on user device. (I'm not sure if android has something like this).

It would be awesome if we could still keep images in one place and use those suffixes as well as optimise our bundle / apk sizes.

[rebeccatownsend-rally]

Metro Symlinks aren't supported by default

We need symlink support to do a lot of things. For me, it's a major headache trying to to develop package dependencies and work with Lerna monorepos without this support. There are currently a few workarounds that the community has shared, but none are one-size-fits all, and it's a major time suck to finesse a fix that works for your specific use case. This should really be something that everyone can leverage out of the box.

[robertying]

Lean Core is great but extracted repos may not be well-attended

I believe Lean Core is a great idea. But I have seen some projects that were previously extracted become inactive. People can get responses quickly from the main repo but not from those repos residing in react-native-community.

Current disappointment:

• react-native-community/react-native-push-notification-ios has a serious issue so you cannot even use pod install to use it now and the pull request has not been taken care of.

[robertying]

Swift not being the default language for iOS

It would be much better for JavaScript programmers (at least for me) to quickly navigate through iOS source code written in Swift than Objective-C which lacks readability compared to the other languages (Java, JavaScript ...). Besides, many examples concerning iOS are now written in Swift. Encouraging Swift in RN projects can make it easier for developers to debug native code or make their own (common case: add custom logics into lifecycle functions).

I personally would like RN to:

• change the default cli generated template from AppDelegate.m, AppDelegate.h and main.m to .swift implementations.

  Flutter cli does give you the option to generate Objective-C & Java template or Swift & Kotlin one.

• encourage new community libraries to be written in Swift for iOS. Rewrite of existing projects would be awesome too!